Metallic gear and method of making the same



March 6,1928. 1,662,026

G. R. BROPHY METALLIC GEAR AND METHOD OF MAKING THE SAME Filed Sept. 2, .1925

Ifivent'or: Gerald R.Bropl g tion, and also the same. j

Patented d, g UNITED STATES GERALD a. mzornx, or SCKENECTADY, NEW Yonx, assrenon ro ennnan.

company, A conronarron on NEW romp l The present invention relates to gears and has for its object to improve their construe- My improved gear is intended especiall .for use where the service or duty is especia ly severe, as-for example, with electric ra1lway motors, but it may, advantageously be used for many other purposes.

Railway gears are commonly made of solid steel billets of circular cross-section in which the fibers, by reason of the forlmngoperations, extend lengthwise. These billets are afterwards cut into suitable lengths to form blanks from which the gears are formed. The purpose of using round billets is to avoid waste of material and to decrease the cost of machine operations. These billets, however, due to the duty required of the gears made therefrom, are relatively expensive.

As a result of the above-mentionedimethod of construction all'or practically all of the fibers in the steel extend lengthwise of the teeth and body whereas to obtain the greatest strength they should extend perpendicularly thereto.

To attain the desired relation of the fibers in the finished gear and also to lessen the effect of flaws, I build up the blank out of steel laminations, which are punched to ap proximate size, using for the purpose sheet stock of say one-eighth inch in thickness, in which the fibers extend generally in the same direction and in which flaws seldom occur. In other words, such stock possesses the important properties of being tough and uniform in texture. Ordinarily, the few flaws which occur in such sheets can readily be detected but if not discovered by reason of being wholly between the side surfaces or for any other reason, no articular harm ,will be done because the de ect is limited to a very small area and generally to a single disk. The disks which form the blank may be smooth on the eriphery but referabl they are provided with unfinis ed teet formed to ap roximately the final shape and size of the ished teeth, allowing a suflicient amount of material machining, so as to reduce the cost of the tooth cutting operation. Where gears of one or a few sizes are to be produced in quantities, the latter method of procedure is superior to the former as will be evident. For my improved method of making the ,trically heated closed furnace in'the or around the mc'rmrc amm- AND un'rnon or uaxme m sum.

Application filed September 2, 1925. Serial Ho. 54,150.

gears, I use a low, carbon sheet steel for subse uen't carbonizing, or amediu m carbon %4050e),thecost ofwhich er'pound- 1s only a fraction of what the billets "cost;

steel I Having punched out the disks and removed the burrs if any on the edges, a suflicient number are stacked to form a finished blank. In the stacking operation it is preferable to angularly displace the disks somewhatone .with respect to the other so that the fibers in the several disks will not all extend in the same direction but will be angularly displaced in the adjacent disks. No particular care need be observed in this respect, if the operators stacking the disks take them from a pile of stock the resulting stack will gen erally be good enough.

The next step is to unite the disks one with the other. This is done by fusion, of metal and for this purpose purified copper is used, the fusion taking place in an elecresmc'raxc I ence of hydrogen or e uivalent non-oxidizing as. When in the urnace, the disks, to obtain the best results, should be retained under ressure to prevent spaces being formed between them.

When a blank made in the manner set forth above is subsequently machined and polished it has the appearance of being made of a single iece, and it is only by careful inspection t at the 'oints between laminations can be detecte The copper used in I J fusing may be placed on top ofthe blank eriphe or it may be distributed both a ove an below the blank as well as aroundit, or very thin sheets placed between laminations. After the blank has been heated to a degree somewhat above the melting point-of copper, the copper W111 flow by cap1l tween the d' with thead'acent surfaces of the steel d1sks. After the sion takes place, the tempera.- ture is reduced to permit the copper to harden after which the blank may be cooled in the 0 en air or in a special cooler as desired. actual tests It has been found that the oint between two pieces of steel united in the mannerset forth is stron er than the steel itself. This is robably no to the alloyin of the steel W1C" the copper. The disks or aminations may be weighted one with the other.

ary action into all of the joints bes and alloy to some extent Another and successful way is to clamp the disks under heavy pressure and when in this condition to unite them by are welding, the welds extending axially. Four such welds would ordinarily be satisfactory but a greater or less number may be employed.

After the blank is removed from the furnace and has cooled the teeth are cut by the usual gear-cutting tools. 'here the blank has teeth formed approximately to size the tooth-cutting operation or finishing is much simplified and the rate of cutting or machining operation correspondingly increased. The gears may afterwards he case-hardened by the usual methods. Blanks made in accordance herewith and afterwards properly machined and polished. show clearly uniform hardening of the steel surfaces. Railway motor pinions made in accordance with my invention are now being used in daily service with successful results.

In the accompanying drawing which is illustrative of my invention, Fig. 1 is an end view of a small gear or pinion; Fig. 2

- is a longitudinal section of the same; and

Fig. 3 is a View in side elevation of a blank showing the temporary means employed to hold the laminations.

4 indicates the relatively thin disks which are punched from sheets of low carbon steel. By preference the teeth 5 are approximately formed to shape and size in the punching operation. To reduce machine work each disk preferably has a central opening. Where the bore of the finished gear is cylindrical the diameter of the openings Wlll I approximate the size of the finished bore but where the bore is to be slightly coned, as shown in Fig. 2, the diameter of the openings will approximate that of the small end of the shaft.

In Fig. 2 the light parallel lines 6 indicate the copper-alloyed joints between the individual disks. In actual practice the joints are very-minute and on a well-polished surface are hardly noticeable. This is due to the fact that the spaces between the disks prior to the actual fusion-are of a capillary nature and hence the amount of copper which enters them is very small indeed.

One way to insure that the spaces between disks shall be of the desired character, the disks, after being properly stacked with the teeth thereon in register, is to subject the stack to heavy endwise pressure, and while so compressed to lightly weld them with an arc welder. Welds of this character are indicated at 7 in Fig. 3. The next step is to fuse the disks into a unitary structure and this is done in an electric furnace in an atmosphere of hydrogen or other non-oxidizing gas. The copper used for fusing can he applied to the blank in any well known way.

A gear to give the most satisfactory results in service should have a relatively soft center with hardened teeth to reduce wear.

To prevent the center from being hardened it is necessary to protect the same in the case-hardening operation. This may be done by any of the well known methods such as copper plating.

What I claim as new and (lOSiIe to secure by Letters Patent of the United States. is:-

1. A gear comprising laminations of sheet steel, which laminations are united by fused copper.

2. A gear comprising laminations of sheet steel in which the fibers thereof extend perpendicular to the axis, said laminations hemg united by fused copper.

3. A gear comprising steel laminations which form the body and the teeth, said laminations being united by fused copper, the teeth being hardened.

4. A gear comprising laminations of sheet steel in which the fibers thereof extend perpendicular to the axis, said laminations being united by fused copper and forming both the body and the teeth, the latter being casehardened. I

5. A gear comprising laminations of sheet steel having a 4050 carbon content in which the fibers thereof extend perpendicular to the axis, said laminations being united by fused copper and forming both the body and the teeth, the latter being hardened.

6. ThB DIBlJlIOd of making gears which comprises punching sheet steel to form disks of approximately the shape and size of the finished gear, assembling the disks in a stack with the fibers of the steel extending perpendicular to the axis, holding the disks under pressure, uniting the disks by fused copper in a non-oxidizing atmosphere, finishing the teeth to exact size and finally hardening the working surfaces of the teeth.

In witness whereof, I have hereunto set my hand this 1st day of September 1925.

G. R. BROPHY. 

